CBS affiliate WGCL-TV in Atlanta reported that Isakson said in a statement, "This information is absolutely false and comes from an unverified source. Senator Isakson has never been affiliated with the KKK." Isakson's office did not respond to CQ Roll Call's request for comment.

Isakson's office told CQ Roll Call the senator is prepared to take legal action over the allegation.

"Senator Isakson has never been affiliated with the KKK," an Isakson aide said. "Because we so firmly believe that this information is libelous and malicious, even under the public official standard, we are prepared to take legal action against any and all who continue to name Johnny Isakson and disseminate this false, unreliable, and unsourced information."

The hacking group Anonymous is scheduled to release on Nov. 5 the alleged identities of 1,000 people associated with the KKK. However, the Monday dump was apparently not part of that initiative , according to one of the group's Twitter accounts.

This account has NOT YET released any information. We believe in due diligence and will NOT recklessly involve innocent individuals #OpKKK
— Operation KKK (@Operation_KKK) November 2, 2015